There are a number of different chemomechanical coupling systems. The most ubiquitous in the actin-myosin-ATP system. Another, also common in eucaryotic cells, is the tubulin-dynin system. In bacteria it appears that energy supplied to the membrane is used via a coupling protein (the mot gene product) which converts it into the rotation of the flagellar filament. The mechanism of this process is not understood. We think that it is fundamental for understanding and affecting bacterial cell function. Our proposal is aimed at elucidating this process and determining how general it is among bacteria and what role it plays in infection. We plan to isolate and study this protein. However, since we have not assay procedures that can specifically detect this protein we have to use less conventional approaches. We plan to use genetic techniques to amplifY the mot genes and to identify the gene products. The products will be isolated and characterized. We will try to determine how it functions, and we will see if analagous proteins would be found in nonflagellated bacteria. Finally, we will set up systems to evaluate the role of motility and chemotaxis in the infectious process.